The mines lie along a broad zone or belt of crystallized carbonate of lime (calcite), which may be seen for many miles traversing the dark-colored inclosing rocks. A huge dike of porphyritic rock cuts across this belt at an angle approaching 90°. The principal mineralization of the lode occurs east of this dike. The country rock is described by F. R. Burnham, E.M., formerly the Superintendent, in his report on the property to the company, as rock more or less schistose in character, through which, at frequent intervals, are intruded eruptive dikes. At the east end of the belt is an accumulation of tufa and basalt. The belt dips south at an angle of 75°. The mineralized portion of this lode extends from the porphyry dike east through three full claims, disappearing finally beneath the eruptive rock and desert wash. The dominant point on the lode is 550 feet above the base of the hill. The entire lode is gold-bearing, some of the iron rock being extremely rich; gold also occurs in the calcite, though it is usually of a lower grade than where accompanied by the iron. Iron sulphide containing gold has been discovered, indicating plainly the origin of the slag-like iron ores and limonite found on the surface. To Mr. Burnham’s report I am also indebted for information concerning the value of the rock, tonnage, and bullion output to date. He has given arbitrary figures for shipments aggregating $37,000, and an estimate on $13,000 more, making a total of $50,000. This ore was milled mostly at the Camp Cady mill and at Hawley’s mill. An arrastra was used in the early history of the mine. The average assays made on a ten days’ mill run just prior to the burning of the mill returned $12 75 per ton. Tailings, during the same period, averaged $1 25. Bullion produced, $1,430. It was found very difficult to sort the ore, though it varied constantly in value from $2 to $20 per ton. About 90 per cent of the assay value, it is claimed, was saved in the mill. In looking through a daily record of assays made in July and August, 1891, I find them to range from a trace to as high as $1,750, most of them running from $6 to $18. Mr. Burnham figures 184,000 tons of mill rock in sight, including all grades, besides large amounts presumed to be available, but not blocked out for stoping. The value of the ore is placed at $5 to $6 throughout. The cost of milling this ore is placed at $2 50, and mining at 50 cents in large stopes. Should the company now controlling the Alvord Mines determine to rebuild their mill it will doubtless again become a bullion producer. ORO GRANDE DISTRICT.